Mechanisms underlying the promotion of functional recovery by deferoxamine after spinal cord injury in rats

Deferoxamine, a clinically safe drug used for treating iron overload, also repairs spinal cord injury although the mechanism for this action remains unknown. Here, we determined whether deferoxamine was therapeutic in a rat model of spinal cord injury and explored potential mechanisms for this effect. Spinal cord injury was induced by impacting the spinal cord at the thoracic T10 vertebra level. One group of injured rats received deferoxamine, a second injured group received saline, and a third group was sham operated. Both 2 days and 2 weeks after spinal cord injury, total iron ion levels and protein expression levels of the proinflammatory cytokines tumor necrosis factor-α and interleukin-1β and the pro-apoptotic protein caspase-3 in the spinal cords of the injured deferoxamine-treated rats were significantly lower than those in the injured saline-treated group. The percentage of the area positive for glial fibrillary acidic protein immunoreactivity and the number of terminal deoxynucleotidyl transferase d UTP nick end labeling-positive cells were also significantly decreased both 2 days and 2 weeks post injury, while the number of Neu N-positive cells and the percentage of the area positive for the oligodendrocyte marker CNPase were increased in the injured deferoxamine-treated rats. At 14–56 days post injury, hind limb motor function in the deferoxamine-treated rats was superior to that in the saline-treated rats. These results suggest that deferoxamine decreases total iron ion, tumor necrosis factor-α, interleukin-1β, and caspase-3 expression levels after spinal cord injury and inhibits apoptosis and glial scar formation to promote motor function recovery.     

脊髓损伤模型大鼠神经修复与法舒地尔和RhoA基因沉默的干预

背景：研究认为Rho激酶可致使神经生长锥塌陷,对神经修复具有抑制作用。 目的：观察Rho激酶抑制剂法舒地尔及RNA干预介导的RhoA基因沉默对脊髓损伤大鼠在体神经损伤修复的作用。 方法：雄性SD大鼠60只半切法制成脊髓半横断模型,随机等分成对照组、法舒地尔组和RhoA siRNA组。法舒地尔组于腹腔注射10 mg/kg法舒地尔,2次/d,连续用药1周;RhoA siRNA干扰组将RhoA siRNA表达质粒注射于大鼠脊髓损伤区。 结果与结论：伤后4周,法舒地尔和RhoA siRNA组大鼠后肢运动功能均有明显恢复,可见少量神经轴索样结构,辣根过氧化物酶阳性神经纤维数增多(P < 0.05),体感诱发电位的潜伏期明显缩短、波幅显著增强(P < 0.05)。提示大鼠脊髓损伤后给予Rho激酶抑制剂法舒地尔及RNA介导的RhoA基因沉默能够促进受损伤的脊髓神经功能恢复。     

Dihydroorotate dehydrogenase regulates ferroptosis in neurons after spinal cord injury via the P53-ALOX15 signaling pathway

Background

Spinal cord injury (SCI) is a highly disabling condition in spinal surgery that leads to neuronal damage and secondary inflammation. Ferroptosis is a non-apoptotic type of cell death that has only recently been identified, which is marked primarily by iron-dependent and lipid-derived reactive oxygen species accumulation, and accompanied by morphological modifications such as mitochondrial atrophy and increase in membrane density. Dihydroorotate dehydrogenase (DHODH) is a powerful inhibitor of ferroptosis and has been demonstrated to inhibit cellular ferroptosis in tumor cells, but whether it can inhibit neuronal injury following spinal cord injury remains ambiguous.

Methods

In this study, the effect of DHODH on neuronal ferroptosis was observed in vivo and in vitro using a rat spinal cord injury model and erastin-induced PC12 cells, respectively. A combination of molecular and histological approaches was performed to assess ferroptosis and explore the possible mechanisms in vivo and in vitro.

Results

First, we confirmed the existence of neuronal ferroptosis after spinal cord injury and that DHODH attenuates neuronal damage after spinal cord injury. Second, we showed molecular evidence that DHODH inhibits the activation of ferroptosis-related molecules and reduces lipid peroxide production and mitochondrial damage, thereby reducing neuronal ferroptosis. Further analysis suggests that P53/ALOX15 may be one of the mechanisms regulated by DHODH. Importantly, we determined that DHODH inhibits ALOX15 expression by inhibiting P53.

Conclusions

Our findings reveal a novel function for DHODH in neuronal ferroptosis after spinal cord injury, suggesting a unique therapeutic target to alleviate the disease process of spinal cord injury.     

Transplantation of erythropoietin gene-modified neural stem cells improves the repair of injured spinal cord

The protective effects of erythropoietin on spinal cord injury have not been well described. Here, the eukaryotic expression plasmid pc DNA3.1 human erythropoietin was transfected into rat neural stem cells cultured in vitro. A rat model of spinal cord injury was established using a free falling object. In the human erythropoietin-neural stem cells group, transfected neural stem cells were injected into the rat subarachnoid cavity, while the neural stem cells group was injected with non-transfected neural stem cells. Dulbecco's modified Eagle's medium/F12 medium was injected into the rats in the spinal cord injury group as a control. At 1–4 weeks post injury, the motor function in the rat lower limbs was best in the human erythropoietin-neural stem cells group, followed by the neural stem cells group, and lastly the spinal cord injury group. At 72 hours, compared with the spinal cord injury group, the apoptotic index and Caspase-3 gene and protein expressions were apparently decreased, and the bcl-2 gene and protein expressions were noticeably increased, in the tissues surrounding the injured region in the human erythropoietin-neural stem cells group. At 4 weeks, the cavities were clearly smaller and the motor and somatosensory evoked potential latencies were remarkably shorter in the human erythropoietin-neural stem cells group and neural stem cells group than those in the spinal cord injury group. These differences were particularly obvious in the human erythropoietin-neural stem cells group. More CM-Dil-positive cells and horseradish peroxidase-positive nerve fibers and larger amplitude motor and somatosensory evoked potentials were found in the human erythropoietin-neural stem cells group and neural stem cells group than in the spinal cord injury group. Again, these differences were particularly obvious in the human erythropoietin-neural stem cells group. These data indicate that transplantation of erythropoietin gene-modified neural stem cells into the subarachnoid cavity to help repair spinal cord injury and promote the recovery of spinal cord function better than neural stem cell transplantation alone. These findings may lead to significant improvements in the clinical treatment of spinal cord injuries.     

甲基强的松龙联合嗅鞘细胞移植对急性脊髓损伤大鼠运动功能和诱发电位的影响

背景：嗅鞘细胞移植和甲基强的松龙是两种非常有前途的治疗脊髓损伤方法,关于二者联合治疗脊髓损伤的报道较少,结果也不尽相同。 目的：通过对大鼠行为学评分和诱发电位学检测了解嗅球嗅鞘细胞移植和甲基强的松龙对大鼠急性脊髓损伤的修复作用以及二者之间有无协同作用。 方法：以NYU脊髓打击法建立大鼠急性T10脊髓损伤模型,术后分别注射嗅鞘细胞、甲基强的松龙、嗅鞘细胞+甲基强的松龙、无血清的DF12培养液、生理盐水。于术后8周进行后肢体感诱发电位、运动诱发电位检测,并通过BBB评分了解各组大鼠手术前、后运动功能的变化。 结果与结论：术后8周,嗅鞘细胞组、甲基强的松龙组、嗅鞘细胞+甲基强的松龙组与损伤组、DF12组比较,大鼠后肢BBB评分明显升高,体感诱发电位、运动诱发电位 N1波潜伏期缩短,波幅升高,差异有显著性意义(P < 0.05)。嗅鞘细胞+甲基强的松龙组与嗅鞘细胞组、甲基强的松龙组比较,大鼠后肢BBB评分明显升高,体感诱发电位、运动诱发电位N1波潜伏期缩短,波幅升高,差异有显著性意义(P < 0.05)。说明嗅鞘细胞移植和甲基强的松龙单独应用均可以显著促进急性脊髓损伤大鼠运动功能恢复。二者联合促进急性脊髓损伤大鼠运动功能恢复的效果更加显著。     

Neuroprotective effects of electroacupuncture on early- and late-stage spinal cord injury

Previous studies have shown that the neurite growth inhibitor Nogo-A can cause secondary neural damage by activating Rho A. In the present study, we hypothesized that electroacupuncture promotes neurological functional recovery after spinal cord injury by inhibiting Rho A expression. We established a rat model of acute spinal cord injury using a modification of Allen's method. The rats were given electroacupuncture treatment at Dazhui(Du14), Mingmen(Du4), Sanyinjiao(SP6), Huantiao(GB30), Zusanli(ST36) and Kunlun(BL60) acupoints with a sparsedense wave at a frequency of 4 Hz for 30 minutes, once a day, for a total of 7 days. Seven days after injury, the Basso, Beattie and Bresnahan(BBB) locomotor scale and inclined plane test scores were significantly increased, the number of apoptotic cells in the spinal cord tissue was significantly reduced, and Rho A and Nogo-A m RNA and protein expression levels were decreased in rats given electroacupuncture compared with rats not given electroacupuncture. Four weeks after injury, pathological tissue damage in the spinal cord at the site of injury was alleviated, the numbers of glial fibrillary acidic protein- and neurofilament 200-positive fibers were increased, the latencies of somatosensory-evoked and motor-evoked potentials were shortened, and their amplitudes were increased in rats given electroacupuncture. These findings suggest that electroacupuncture treatment reduces neuronal apoptosis and decreases Rho A and Nogo-A m RNA and protein expression at the site of spinal cord injury, thereby promoting tissue repair and neurological functional recovery.     

Partial recovery after treatment of chronic paraplegia in rat

While acute spinal cord injury has been the object of intensive research, chronic spinal cord injury has received less attention although most clinical cases of spinal cord injury become chronic. We attempted to surgically "repair" chronic and acute spinal cord injury in a complete transection rat model using a multiple peripheral nerve grafting protocol. The lesion extent was assessed by magnetic resonance imaging (MRI) before the repair procedure. Rats were treated immediately after injury or at 2, 4, or 8 months postinjury. Standard behavioral methods were used to evaluate functional recovery. Two novel tests, the Bipedal Test and the Head-scratch test, were also employed to evaluate hindpaw positioning, interlimb coordination, and stepping rhythmicity, and to indicate rostrocaudal pathway regeneration. MRI helped guide the treatment procedure that was applied to animals with chronic injury. Treated animals demonstrated significant motor recovery. Axonal regeneration resultant to treatment was demonstrated histologically. The results suggest that not only acute but also chronic total paraplegia can be reversed to a moderate degree in rats with regard to hindlimb motor function.     

嗅鞘细胞移植治疗脊髓损伤的临床验证

背景: 一系列基础研究证实在动物脊髓损伤的模型中,嗅鞘细胞移植能够促进脊髓损伤的再生和恢复脊髓的部分神经功能。部分临床实验证明嗅鞘细胞的移植的确能改善脊髓损伤患者的神经功能,从而改善其生活质量。 目的：验证嗅鞘细胞移植对脊髓损伤患者神经功能修复的作用及安全性。 方法：取流产胚胎嗅球并消化成为单个嗅鞘细胞,培养纯化2周左右,制成嗅鞘细胞悬液。选择脊髓损伤患者213例,全麻下将制备好的嗅鞘细胞悬液采用区域性多靶点注射方法移植于损伤脊髓的周围。采用ASIA量表对患者移植前1d及移植后3周~2个月进行评分,评价患者脊髓恢复状况。 结果与结论：所有患者的脊髓神经功能于术后3周均有不同程度的改变,脊髓功能评分及感觉与运动功能均较移植前明显提高(P < 0.001),且随时间延长呈不断改善趋势;最长患者随访5年,未见已恢复的神经功能 减退及移植不良反应。证实嗅鞘细胞移植对脊髓损伤患者的神经功能恢复有促进作用,可以部分恢复及改善其部分脊髓神经功能,且治疗方法安全。     

Nischarin-siRNA delivered by polyethylenimine-alginate nanoparticles accelerates motor function recovery after spinal cord injury

A previous study by our group found that inhibition of nischarin promotes neurite outgrowth and neuronal regeneration in Neuro-2 a cells and primary cortical neurons.In recent years,more and more studies have shown that nanomaterials have good prospects in treatment of spinal cord injury.We proposed that small interfering RNA targeting nischarin(Nis-si RNA) delivered by polyethyleneimine-alginate(PEIALG) nanoparticles promoted motor function recovery in rats with spinal cord injury.Direct microinjection of 5 μL PEI-ALG/Nis-si RNA into the spinal cord lesion area of spinal cord injury rats was performed.From day 7 after surgery,Basso,Beattie and Bresnahan score was significantly higher in rats from the PEI-ALG/Nis-si RNA group compared with the spinal cord injury group and PEI-ALG/Control-si RNA group.On day 21 after injection,hematoxylin-eosin staining showed that the necrotic area was reduced in the PEI-ALG/Nis-si RNA group.Immunohistochemistry and western blot assay results confirmed successful inhibition of nischarin expression and increased protein expression of growth-associated protein-43 in the PEI-ALG/Nis-si RNA group.These findings suggest that a complex of PEI-ALG nanoparticles and Nis-si RNA effectively suppresses nischarin expression,induces expression of growth-associated protein-43,and accelerates motor function recovery after spinal cord injury.     

Aldehyde dehydrogenase 2 overexpression inhibits neuronal apoptosis after spinal cord ischemia/reperfusion injury

Aldehyde dehydrogenase 2(ALDH_2)is an important factor in inhibiting oxidative stress and has been shown to protect against renal ischemia/reperfusion injury.Therefore,we hypothesized that ALDH_2 could reduce spinal cord ischemia/reperfusion injury.Spinal cord ischemia/reperfusion injury was induced in rats using the modified Zivin’s method of clamping the abdominal aorta.After successful model establishment,the agonist group was administered a daily consumption of 2.5%alcohol.At 7 days post-surgery,the Basso,Beattie,and Bresnahan score significantly increased in the agonist group compared with the spinal cord ischemia/reperfusion injury group.ALDH_2expression also significantly increased and the number of apoptotic cells significantly decreased in the agonist group than in the spinal cord ischemia/reperfusion injury group.Correlation analysis revealed that ALDH_2 expression negatively correlated with the percentage of TUNEL-positive cells(r=-0.485,P0.01).In summary,increased ALDH_2 expression protected the rat spinal cord against ischemia/reperfusion injury by inhibiting apoptosis.     

Local injection of bone morphogenetic protein 7 promotes neuronal regeneration and motor function recovery after acute spinal cord injury

After spinal cord injury,the number of glial cells and motor neurons expressing bone morphogenetic protein 7(BMP7)increases,indicating that upregulation of BMP7 can promote nerve repair.We,therefore,tested whether direct injection of BMP7 into acutely injured ratalalo createrywith 50 ng BMP7(BMP7 group)or physiological saline(control group)for 7 consecutive days.Electrophysiological examination showed that the amplitude of N1 in motor evoked potentials(MEP)decreased after spinal cord injury.At 8 weeks post-operation,the amplitude of N1 in the BMP7 group was remarkably higher than that at 1 week post-operation and was higher than that of the control group.Basso,Beattie,Bresnahan scale(BBB)scores,hematoxylin-eosin staining,and western blot assay showed that at 1,2,4 and 8 weeks post-operation,BBB scores were increased;Nissl body staining was stronger;the number of Nissl-stained bodies was increased;the number of vacuoles gradually decreased;the number of synapses was increased;and the expression of neuronal marker,neurofilament protein 200,was increased in the hind limbs of the BMP7 group compared with the control group.Western blot assay showed that the expression of GFAP protein in BMP7 group and control group did not change significantly and there was no significant difference between the BMP7 and control groups.These data confirmed that local injection of BMP7 can promote neuronal regeneration after spinal cord injury and promote recovery of motor function in rats.     

脊髓缺血再灌注损伤时血清及脊髓组织一氧化氮水平的动态变化及意义

目的 观察一氧化氮(NO)在脊髓缺血再灌注损伤(SCIRI)时血清及脊髓组织中的变化,探讨其在SCIRI中的意义. 方法 采用Zivin法建立家兔SCIRI模型,动态观察NO在血清和脊髓组织中的表达. 结果 血清NO在缺血再灌注(IRI)组缺血末期明显上升,IRI后2 h达到峰值,与缺血前比较差异有统计学意义(P<0.05),IRI后6 h、12 h明显降低,与缺血前及Sham组比较差异有统计学意义(P<0.05);脊髓组织中NO在缺血末期明显升高并达到峰值,缺血再灌注后2h、6 h逐渐下降,与Sham组比较差异有统计学意义(P<0.05),缺血再灌注后12 h下降到Sham组水平. 结论 NO在SCIRI后血清和脊髓组织中表达增高,可能在SCIRI病理过程神经元损伤与修复中发挥一定作用.     

Jisuikang,a Chinese herbal formula,increases neurotrophic factor expression and promotes the recovery of neurological function after spinal cord injur y

The Chinese medicine compound, Jisuikang, can promote recovery of neurological function by inhibiting lipid peroxidation, scavenging oxygen free radicals, and effectively improving the local microenvironment after spinal cord injury. However, the mechanism remains unclear. Thus, we established a rat model of acute spinal cord injury using a modified version of Allen's method. Jisuikang(50, 25, and 12.5 g/kg/d) and prednisolone were administered 30 minutes after anesthesia. Basso, Beattie, and Bresnahan locomotor scale scores and the oblique board test showed improved motor function recovery in the prednisone group and moderate-dose Jisuikang group compared with the other groups at 3–7 days post-injury. The rats in the moderate-dose Jisuikang group recovered best at 14 days post-injury. Hematoxylin-eosin staining and transmission electron microscopy showed that the survival rate of neurons in treatment groups increased after 3–7 days of administration. Further, the structure of neurons and glial cells was more distinct, especially in prednisolone and moderate-dose Jisuikang groups. Western blot assay and immunohistochemistry showed that expression of brain-derived neurotrophic factor(BDNF) in injured segments was maintained at a high level after 7–14 days of treatment. In contrast, expression of nerve growth factor(NGF) was down-regulated at 7 days after spinal cord injury. Real-time fluorescence quantitative polymerase chain reaction showed that expression of BDNF and NGF m RNA was induced in injured segments by prednisolone and Jisuikang. At 3–7 days after injury, the effect of prednisolone was greater, while 14 days after injury, the effect of moderate-dose Jisuikang was greater. These results confirm that Jisuikang can upregulate BDNF and NGF expression for a prolonged period after spinal cord injury and promote repair of acute spinal cord injury, with its effect being similar to prednisolone.     

Contribution of bone marrow‐derived endothelial progenitor cells to neovascularization and astrogliosis following spinal cord injury

Spinal cord injury causes initial mechanical damage, followed by ischemia‐induced, secondary degeneration, worsening the tissue damage. Although endothelial progenitor cells (EPCs) have been reported to play an important role for pathophysiological neovascularization in various ischemic tissues, the EPC kinetics following spinal cord injury have never been elucidated. In this study, we therefore assessed the in vivo kinetics of bone marrow‐derived EPCs by EPC colony‐forming assay and bone marrow transplantation from Tie2/lacZ transgenic mice into wild‐type mice with spinal cord injury. The number of circulating mononuclear cells and EPC colonies formed by the mononuclear cells peaked at day 3 postspinal cord injury. Bone marrow transplantation study revealed that bone marrow‐derived EPCs recruited into the injured spinal cord markedly increased at day 7, when neovascularization and astrogliosis drastically occurred in parallel with axon growth in the damaged tissue. To elucidate further the contribution of EPCs to recovery after spinal cord injury, exogenous EPCs were systemically infused immediately after the injury. The administered EPCs were incorporated into the injured spinal cord and accelerated neovascularization and astrogliosis. These findings suggest that bone marrow‐derived EPCs may contribute to the tissue repair by augmenting neovascularization and astrogliosis following spinal cord injury. © 2012 Wiley Periodicals, Inc.     

Three-dimensional bioprinting collagen/silk fibroin scaffold combined with neural stem cells promotes nerve regeneration after spinal cord injury

Many studies have shown that bio-scaffolds have important value for promoting axonal regeneration of injured spinal cord.Indeed,cell transplantation and bio-scaffold implantation are considered to be effective methods for neural regeneration.This study was designed to fabricate a type of three-dimensional collagen/silk fibroin scaffold (3D-CF) with cavities that simulate the anatomy of normal spinal cord.This scaffold allows cell growth in vitro and in vivo.To observe the effects of combined transplantation of neural stem cells (NSCs) and 3D-CF on the repair of spinal cord injury.Forty Sprague-Dawley rats were divided into four groups: sham (only laminectomy was performed),spinal cord injury (transection injury of T10 spinal cord without any transplantation),3D-CF (3D scaffold was transplanted into the local injured cavity),and 3D-CF + NSCs (3D scaffold co-cultured with NSCs was transplanted into the local injured cavity.Neuroelectrophysiology,imaging,hematoxylin-eosin staining,argentaffin staining,immunofluorescence staining,and western blot assay were performed.Apart from the sham group,neurological scores were significantly higher in the 3D-CF + NSCs group compared with other groups.Moreover,latency of the 3D-CF + NSCs group was significantly reduced,while the amplitude was significantly increased in motor evoked potential tests.The results of magnetic resonance imaging and diffusion tensor imaging showed that both spinal cord continuity and the filling of injury cavity were the best in the 3D-CF + NSCs group.Moreover,regenerative axons were abundant and glial scarring was reduced in the 3D-CF + NSCs group compared with other groups.These results confirm that implantation of 3D-CF combined with NSCs can promote the repair of injured spinal cord.This study was approved by the Institutional Animal Care and Use Committee of People’s Armed Police Force Medical Center in 2017 (approval No.2017-0007.2).     

高压氧联合神经干细胞移植治疗大鼠脊髓损伤

背景：单纯神经干细胞移植已应用于对受损脊髓组织的修复。 目的：以神经干细胞移植同时应用高压氧治疗大鼠脊髓损伤,观察联合作用对脊髓损伤大鼠运动功能恢复的影响。 方法：雌性SD大鼠60只,以半切法制成胸段脊髓半横断大鼠模型。随机分成单纯损伤组、神经干细胞移植组及高压氧治疗组,每组20只。伤后第4周取材行病理切片苏木精-伊红染色及BrdU免疫组织化学染色,第8周取材行辣根过氧化物酶示踪,透射电镜观察轴突的再生情况,通过体感诱发电位观察神经电生理恢复情况。造模后1,2,4,6,8周进行BBB评分和斜板实验等运动功能检测。 结果与结论：观察伤后4周病理切片,单纯损伤组未见神经轴索通过,神经干细胞移植组可见少量神经轴索样结构,高压氧治疗组可见较多神经轴索样结构。BrdU的阳性细胞数及辣根过氧化物酶阳性神经纤维数,高压氧治疗组最多,神经干细胞移植组次之,单纯损伤组最少,且各组之间差异有显著性意义(P < 0.05)。透射电镜下神经干细胞移植组、高压氧治疗组正中横断面可见新生的无髓及有髓神经纤维。高压氧治疗组大鼠体感诱发电位的潜伏期短于神经干细胞移植组,波幅高于神经干细胞移植组(P < 0.05),明显优于单纯损伤组(P < 0.01)。伤后4周神经干细胞移植组、高压氧治疗组大鼠后肢运动功能均有较明显恢复,高压氧治疗组较神经干细胞移植组恢复快(P < 0.05);单纯损伤组亦有所恢复,但程度较轻。提示神经干细胞移植对于脊髓损伤大鼠后肢功能的恢复有促进作用,联合应用高压氧有协同效果。     

Therapeutic efficacy of SJA6017, a calpain inhibitor, in rat spinal cord injury

Apoptosis is an important element of the secondary processes that occur after spinal cord injury. Calpain and caspases are key proteases in apoptotic cell death. We evaluated the neuroprotective effects of SJA6017 (a calpain inhibitor) and measured functional recovery in a rat spinal cord injury model. Thirty Wistar albino rats were divided into three groups of 10 animals each: sham-operated (group 1), trauma control (group 2) and trauma-plus-SJA6017 treatment (group 3). Spinal cord trauma was produced in the thoracic region of the animals. Rats in group 3 received SJA6017 1 min after trauma. Treatment efficacy was evaluated after injury using light microscopy and TUNEL staining. Neurological performance was assessed using an inclined plane and a modified version of the Tarlov's grading scale. Group 2 rats showed moderate trauma with widespread edema, hemorrhage, vascular thrombi and necrosis 24 h after injury. Group 3 rats had significantly reduced tissue injury and apoptosis. Tarlov scores revealed that group 3 rats also had ameliorated recovery of limb function. Our results demonstrate that treatment with SJA6017 reduces apoptotic cell death, preserves spinal cord tissue and improves functional outcome. Treating calpain-induced apoptosis with this agent may be a feasible therapeutic strategy for patients with spinal cord injury.     

Collagen scaffold combined with human umbilical cord-mesenchymal stem cells transplantation for acute complete spinal cord injury

Currently, there is no effective strategy to promote functional recovery after a spinal cord injury. Collagen scaffolds can not only provide support and guidance for axonal regeneration, but can also serve as a bridge for nerve regeneration at the injury site. They can additionally be used as carriers to retain mesenchymal stem cells at the injury site to enhance their effectiveness. Hence, we hypothesized that transplanting human umbilical cord-mesenchymal stem cells on collagen scaffolds would enhance healing following acute complete spinal cord injury. Here, we test this hypothesis through animal studies and a phase I clinical trial.(1) Animal experiments: Models of completely transected spinal cord injury were established in rats and canines by microsurgery. Mesenchymal stem cells derived from neonatal umbilical cord tissue were adsorbed onto collagen scaffolds and surgically implanted at the injury site in rats and canines;the animals were observed after 1 week–6 months. The transplantation resulted in increased motor scores, enhanced amplitude and shortened latency of the motor evoked potential, and reduced injury area as measured by magnetic resonance imaging.(2) Phase I clinical trial: Forty patients with acute complete cervical injuries were enrolled at the Characteristic Medical Center of Chinese People's Armed Police Force and divided into two groups. The treatment group(n = 20) received collagen scaffolds loaded with mesenchymal stem cells derived from neonatal umbilical cordtissues;the control group(n = 20) did not receive the stem-cell loaded collagen implant. All patients were followed for 12 months. In the treatment group, the American Spinal Injury Association scores and activities of daily life scores were increased, bowel and urinary functions were recovered, and residual urine volume was reduced compared with the pre-treatment baseline. Furthermore, magnetic resonance imaging showed that new nerve fiber connections were formed, and diffusion tensor imaging showed that electrophysiological activity was recovered after the treatment. No serious complication was observed during follow-up. In contrast, the neurological functions of the patients in the control group were not improved over the follow-up period. The above data preliminarily demonstrate that the transplantation of human umbilical cord-mesenchymal stem cells on a collagen scaffold can promote the recovery of neurological function after acute spinal cord injury. In the future, these results need to be confirmed in a multicenter, randomized controlled clinical trial with a larger sample size. The clinical trial was approved by the Ethics Committee of the Characteristic Medical Center of Chinese People's Armed Police Force on February 3, 2016(approval No. PJHEC-2016-A8). All animal experiments were approved by the Ethics Committee of the Characteristic Medical Center of Chinese People's Armed Police Force on May 20, 2015(approval No. PJHEC-2015-D5).     

Utility of somatosensory and motor-evoked potentials in reflecting gross and fine motor functions after unilateral cervical spinal cord contusion injury

Fine motor skills are thought to rely on the integrity of ascending sensory pathways in the spinal dorsal column as well as descending motor pathways that have a neocortical origin.However, the neurophysiological processes underlying communication between the somatosensory and motor pathways that regulate fine motor skills during spontaneous recovery after spinal cord contusion injury remain unclear.Here, we established a rat model of cervical hemicontusive injury using C5 laminectomy followed by contusional displacement of 1.2 mm(mild injury) or 2.0 mm(severe injury) to the C5 spinal cord.Electrophysiological recordings were performed on the brachial muscles up to 12 weeks after injury to investigate the mechanisms by which spinal cord pathways participate in motor function.After spinal cord contusion injury, the amplitudes of somatosensory and motor-evoked potentials were reduced, and the latencies were increased.The forelimb open field locomotion test, grooming test, rearing test and Montoya staircase test revealed improvement in functions.With increasing time after injury, the amplitudes of somatosensory and motor-evoked potentials in rats with mild spinal cord injury increased gradually, and the latencies gradually shortened.In comparison, the recovery times of somatosensory and motor-evoked potential amplitudes and latencies were longer, and the recovery of motor function was delayed in rats with severe spinal cord injury.Correlation analysis revealed that somatosensoryevoked potential and motor-evoked potential parameters were correlated with gross and fine motor function in rats with mild spinal cord contusion injury.In contrast, only somatosensory-evoked potential amplitude was correlated with fine motor skills in rats with severe spinal cord injury.Our results show that changes in both somatosensory and motor-evoked potentials can reflect the changes in gross and fine motor functions after mild spinal cord contusion injury, and that the change in somatosensory-evoked potential amplitude can also reflect the change in fine motor function after severe spinal cord contusion injury.This study was approved by the Animal Ethics Committee of Nanfang Hospital, Southern Medical University, China(approval No.NFYY-2017-67) on June 11, 2017.